I'm making regular backup of my pictures on external hard drive with dedicated software (Cobian backup). I'm using incremential backup so that only modified pictures will be updated. In case of ransomware, I saw that one can crypt your picture WITHOUT changing file name / extension. So, if the file date is changed and the size, my backup tool maybe replace my good picture by the crypted one.
Although it would be good, I don't allow multiple copy of the picture (sorted by time) because of mess it is creating.
So my question is :
Is there a tool to scan my disk and check that all file are really picture. I think that, by scanning the header of a file, it's possible to know the real type, whatever the extension. In such case, I could search for all files that are not JPG. If I don't find any, my files are safe / clean and I can do the backup without concern
Hope it is clear and in the right forum